The invention relates to a control system with a controlling element for controlling the output of an internal combustion engine followed by manual transmission, in which signals can be fed to the control system from a speed transmitter in order to limit the maximum speed of a vehicle driven by the internal combustion engine.
In control systems such as are present, for instance, in the case of an electric gas pedal with vehicular speed speed limitation, it may be necessary, under certain conditions, that the limiting be temporarily done away with and/or replaced by a different limit. This is true in the case of vehicles with unsynchronized manual transmissions in which, in order to shift to a lower gear, the gearwheels in the transmission on the drive side and the driven side must be brought to the same peripheral speed in order to make smooth engagement possible. This is effected by "the intermediate giving of gas" in the neutral position of the transmission without the clutch being disengaged.
If the vehicle is at its maximum permissible speed and if the power controlling member is adjusted downward by the control system as a result of a corresponding signal from a speed transmitter, then it is not possible for the driver to shift back into a lower gear since the controlling element does not permit an intermediate giving of gas, as a result of the downward regulation which has been carried out. Down shifting at such high vehicular speeds into a lower gear may be necessary in the case of large downgrades. After a few seconds, however, in the case of an unsuccessful attempt, the shifting into the previous gear is also no longer possible since such a low speed of rotation has been regulated down in the meantime on the internal combustion engine that the peripheral speeds of the gears which comes into engagement with each other are again not adapted to each other. In this case the braking power of the internal combustion engine cannot be utilized and the driver of the vehicle is dependent in this condition solely on the brake system, which can lead to critical situations on longer downgrades.